Bracing for white nose syndrome

Western scientists take precautions against a deadly bat disorder

 

When the members of Boy Scout Troop 958 emerged from Fort Stanton Cave near Ruidoso, N.M., into the bright August day, they headed immediately to a nearby restroom. There they shed their muddy clothes, kneepads and gloves, stuffing them into plastic Wal-Mart bags. They took the bags to the cave bunkhouse, some distance from the restroom, and tossed everything into washing machines. Then they plopped their helmets into a barrel of disinfectant and swabbed their headlamps with disinfecting wipes.

The sanitation efforts were meant to help protect bats from a disease called white nose syndrome. It's killed over a million bats in the Eastern United States since 2006, but it hasn't hit the West -- yet. The disease is likely caused by a cold-loving fungus that strikes bats during winter hibernation, when their lower body temperature allows it to take hold. It's called white nose syndrome because it smudges the bats' faces and wings with white.

Similar fungi (think athlete's foot), annoy, but don't kill. Scientists suspect this particular fungus annoys the bats so much that it disrupts their hibernation: They wake up to scratch and groom it away, using up their fat reserves and starving to death before food becomes available in spring. The syndrome has wiped out nearly all of the bats in the caves it hits.

In the East, wildlife managers have been powerless to stop the fungus, which is thought to spread when bats rub against each other during hibernation, in maternity colonies and while mating. But humans may play a role in moving it from region to region and even from continent to continent. White nose syndrome was unknown in the U.S. before 2006, but bats with a similar white fuzz on their faces and wings had been seen for decades in Europe, where the syndrome does not appear to be lethal.

Land managers and wildlife biologists are divided on whether white nose syndrome will come to the West. Some believe it is inevitable, and that the threat to Western bats has grown since mid-April, when white nose syndrome was confirmed for the first time west of the Mississippi River, in a cave in eastern Missouri. "I think you would have to be terribly naïve to think that the sites in the West haven't been at risk," says Pat Ormsbee, a bat biologist for the U.S. Forest Service who serves as white nose syndrome committee chair for the Western Bat Working Group.

It's not just human travelers who might carry white nose syndrome from East to West; there are three bat species whose ranges span the continent, says Ormsbee. Back East, these bats mingle with others of their kind from hundreds of miles away. If Western bats behave like their Eastern cousins, it may give white nose syndrome a path to the West.

Some scientists believe that Western caves are generally too warm and dry to support the fungus, though, and that the region's bat hibernation colonies are too small and spread-out for white nose syndrome to take root. Scientists don't even know where most of the bat hibernation caves in the West are. "For the number of bats we see in the summer," Ormsbee says, "we don't know where they go in the winter."

The  West is home to roughly 30 bat species, two of which are endangered: the lesser long-nosed in Arizona and New Mexico, and the Mexican long-nosed in New Mexico and Texas. Another rare species of bat, Townsend's big-eared, hibernates in Fort Stanton Cave. This bat has a scrunched-up face and ears that would do a jackrabbit proud. Its numbers have been declining, and two Eastern subspecies are federally endangered.

Bats are a key part of any ecosystem they inhabit. They eat bugs, literally tons of them. Bat Conservation International once calculated that one colony of about 20 million bats near its home city of Austin, Texas, ate 250 tons of insects a night. Given the importance of bats, "we have to do everything possible to defeat this thing," says Mike Bilbo, Bureau of Land Management cave program manager for Fort Stanton.